(a) During the first 50 hours of life a warming up time of 10 minutes
is required. A further 5 minutes may be required for the HT to be increased
to its full value. After 50 hours of use a 2 minute warming up time is sufficient
provided the valve has been operating during the previous 50 hours - otherwise a 10 minute warming up period is required.
(b) These ratings are for operation with

repetition frequency of 1000 pps

pulse length of 1.25µs

sensibly square pulse shape

load resistance of 17.5 ohms

anode cooling by an air stream at 2.5" ± 0.5" water head

DC resonant charging

(c) The trigger pulse should be between 1 and 3µs long at the 500V
(or higher) level. The source impedance of the trigger pulse generator should be
between 250 and 500 ohms. The DC resistance of the grid-cathode circuit
should not exceed 2000 ohms.
(d) The valve contains a hydrogen replenisher and therefore cannot be
used much below the ratings given
(e) No object should be placed within 1" of the glass of the valve
during operation